The present invention relates to a cultivator having a blade which cultivates the soil with air injected from a nozzle or injector provided on a lower portion of the blade which is forced into the soil and moved by a tractor.
Japanese Utility Model Laid-Open Nos. 57-125201 and 59-29102, for example, disclose cultivators each provided with an aerating device, attached to a tractor by a three-point linkage. The cultivator has a long vertical blade provided with an injector at a lower portion thereof.
Such a cultivator is constructed to continuously inject compressed air from the injector at predetermined intervals. The cultivator is lowered by the three-point linkage to the surface of a field or fruit garden, and further the blade with the injector is inserted in the soil to a predetermined sufficient depth to perform desired deep cultivation. The cultivation and aeration are performed while the tractor advances. When the operation is over, the cultivator is raised by the three-point linkage above the ground.
However, if the air is injected before the blade and injector reach the predetermined depth, the compressed air will spout out with blowing up the soil. Consequently, holes are made in the field thereby affecting plants cultivated therein.